1. Field of the Invention
The present invention relates to broadband microwave integrated circuits, and in particular to coplanar microwave balun, multiplexer and mixer assemblies.
2. Description of the Prior Art
The desire to provide broadband microwave integrated circuits has forced a new look at methods of multiplexing two signals on a common coplanar line. There have been extensive studies on methods to launch single signals onto slot lines and coplanar waveguide lines, but few have been directed towards launching multiple signals onto a common line. These studies have focused on techniques that are complex in realization and limited in bandwidth.
Accordingly, one objective of the present invention is to provide coplanar microwave assemblies operative over wide bandwidths, for multiplexing two microwave signals onto a common line. The microwave signals will propagate down the common line in different modes. Another objective is to provide such assemblies in which the two input ports are electrically isolated from each other.
Various types of microwave devices can be advantageously constructed utilizing such wideband coplanar multiplexing techniques. These include balanced mixers, balanced modulators and balanced frequency multipliers. Such devices take advantage of the concurrent propagation on a single line in different modes of two microwave signals. Thus a further objective of the present invention is to provide microwave coplanar integrated circuit mixers and modulators, having the characteristics of broad bandwidth, low VSWR and simple structure.